Erratic running when hot

[CMF_Garth]

Hi all,
This is my first post, and I hope someone can help.
I have a 1993 K11, and it appears to be displaying all the symptoms of a Throttle Body problems. The car Starts and runs perfectly, until it gets really hot, then it starts to run lumpy, and the Tacho needle seems to skip, drop and fluctuate. The car can still be driven, but it feels all wrong. Having searched numerous posts, I found the fix of resoldering the Air Mass connections, this was done, but still the same problem. I then decided to buy a second hane Throttle body which is now on the car, and the problem is the same. This too I have resoldered.

Problem still remains when the car gets hot.

Hope someone has some ideas, all gratefully received

 

[CMF_frank2]

Maybe the coolant temp sensor garth ? Which is the 2 wire one under the dizzy, there are a few threads on here

 

[CMF_Garth]

Hi Frank,
I did see a couple of threads regarding the Temp sensor, and had been pricing them up. Thought I would come on here and see whwt the experts thought.

Thanks for the response

 

[CMF_demonical]

"Tacho needle seems to skip, drop and fluctuate" Blame me but i think it has nothing to do with the sensors try to get another dizzy to swap and be very careful the slot where it meet's the cam is off center a bit

 

[CMF_RTK]

Had a similar problem with mine, but did it all the time first thing replace the Distributor get a new one is preferable, but when you do make sure you line up your timing marks, and then take the dizzy cap off setting the rotor to cyl 1 then bolt it in and everything you pulled off and off you go no problems

 

[CMF_frank2]

demonical WROTE:

""Tacho needle seems to skip, drop and fluctuate" Blame me but i think it has nothing to do with the sensors try to get another dizzy to swap and be very careful the slot where it meet's the cam is off center a bit

My tacho skips, drops and fluctuates if the rpm drops below about 500

 

[CMF_Garth]

Hi all,
Thanks for the advice, I have now changed the distributor, and the Temp sensor, but after 15/20 mins the car still starts running poorly, I am now thinking about HT leads and coil, has anyone any comments or other advice, before I splash out on those?

Thanks

 

[CMF_jesse]

Hi there!
Did You find the problem eventually?
I have the same problem on my -95 k11 and I have tried everything I can think of: including new dizzy, new ECU, soldered AFM etc...

 

[CMF_jesh]

Hi,
I think you should perform a complete scan test to see if any DTC`s stores.

 

[CMF_jesse]

I have read the error codes from the ECU, nothing...
Today I checked the timing with a lamp and discovered that the ingintion advance on some cylinders is fluctuating. About 10degs on cyl 3 and 20degs on cyl 4.
But cylinders 1 and 2 seem to be stable.
I'm really lost with this. What on earth can make ignition timing fluctuate on only two cylinders?!

 

[CMF_frank2]

jesse WROTE:

What on earth can make ignition timing fluctuate on only two cylinders?!

slack chains maybe jesse ? rock the crank pulley and check the rotor arm movement

 

[CMF_jesh]

What is the actual mileage. I agree with Frank of the slack chain. This is sometimes create erratic running of the engine.

 

[CMF_jesse]

Really? Timing chain?
Sounds strange to me but on the other hand I have tried everything else...
Thanks for the idea, I have to check the rotor movement next.
If this is the problem, does it mean that the chain tensioners a faulty?

The mileage is about 130 000 km.

 

[CMF_frank2]

my lower chain tensioner oilfeed hole blocked once, and the cams went really jittery and noisy (with spark scatter too)
the upper chain tensioner has a ratchet mechanism inside that stops it retracting when the oil drains from it overnight, but it may have been removed but not unlocked after refit ?